The long-term goal of this project is to design and evaluate practical image enhancement methods that would enable people with impaired vision, particularly those with central field loss due to age-related macular disease, to enjoy and benefit from the spread of video technology. Towards this goal, we are developing enhancement methods and investigating factors affecting patient performance with, and the appearance of, enhanced images. Our work is guided by our evolving vision model of contrast perception that we (and others) use in developing, testing, and refining image enhancement techniques. We believe that a basic understanding of contrast and image perception is essential for progress in this area, and that our clinical and basic research efforts usefully interact with each other in ways that benefit both. In this proposal we emphasize more-directly-applicable aspects of the project by developing new ways to measure preference and perceived image quality for video sequences, and by evaluating improved and new enhancement algorithms. We continue our investigation of form vision in patients with central field loss and of the possible role of brain plasticity in this process. We also continue to investigate the possible impact of short-term adaptations to blur and sharpness in reducing the perceived improvement of perception with enhancements, and possible ways to counter these effects. Specifically, we will evaluate the properties of our new method for measuring instantaneous image quality in motion videos and its value in studying image enhancement as well as the image degradation caused by digital compression. We will implement and evaluate a method of pairwise comparison to quantify preferences for enhancement, and apply these evaluation techniques in the selection of enhancement parameters and assessment of image quality. We will evaluate: our adaptive enhancement algorithm (as implemented on an inexpensive consumer product), an improved nonlinear version of that algorithm, and an enhancement for digital video designed to work directly in the compression (MPEG) domain. We will also evaluate the benefit of newly-available high brightness and high dynamic range displays. We will continue our psychophysical studies, in an effort to understand the adaptations and changes that affect patients who lose their central retina.